Applicant claims, under 35 U.S.C. xc2xa7119, the benefit of priority of the filing date of Jul. 17, 1998 of a German patent application, copy attached, Ser. No. 198 32 108.2, filed on the aforementioned date, the entire contents of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an angle measuring system for measuring the angular position of two objects which are rotatable around an axis in relation to each other. It further relates to a method for mounting the angle measuring system.
2. Discussion of Related Art
Such an angle measuring system and such a method are known from U.S. Pat. No. 4,942,295. The described angle measuring systems do not have their own bearings. To make attachment to the objects to be measured easier, the position correlation of the graduation support and the scanning device, which is necessary for operation, has already been fixed by the manufacturer of the angle measuring system by pre-mounting. To this end, an annular groove has been cut in the hub to which the graduation support is attached. Two fixation elements in the form of projections have been formed on the scanning device, which can be radially displaced by means of pressure elements and in the pre-mounted state engage the groove in the hub and in this way fix the axial position correlation between the scanning device and the graduation support.
The disadvantage of this angle measuring system lies in that the position of the groove must be exactly matched to the position and tolerances of the projections already in the course of the manufacturing process. Thus, very narrow tolerances have to be maintained during the manufacturing process, which makes production more expensive. It is moreover known that in connection with graduation supports having an incremental graduation, the required scanning distance is a function of the graduation period. Therefore the position of the groove must be individually exactly manufactured as a function of the graduation period. This requires the manufacture, as well as the storage of different hubs.
The invention is based on the object of providing an angle measuring system, wherein the required correlation between the graduation support and the scanning device can be preset in a simple manner and which can be simply produced.
This object is attained by the angle measuring system for measuring the angular position of two objects which are rotatable around an axis in relation to each other and includes a support with a graduation, wherein the support can be connected on a first object. A scanning device which can be fastened on a second object. A clamping element which fixes at least the axial positional relationship between the graduation and the scanning device before and during their mounting on the first and second objects, wherein the clamping element and/or the support are deformed by being radially pressed together in a clamping area, and this deformation causes at least an axially acting interlocking connection between the scanning device and the support.
The particular advantages of the angle measuring system of the present invention rest in that the required correlation between the graduation support and the scanning device can be simply fixed in at least the axial direction without it being necessary, when producing the scanning device and the hub, to take this correlation into consideration.
A second object of the invention to provide a method for pre-mounting an angle measuring system, which makes a simple correlation between the graduation support and the scanning device possible.
The second object is attained by the a method for mounting an angle measuring system that includes setting a scanning distance (a) between a graduation and a scanning device of an angle measuring system and creating an interlocking connection between the scanning device and a support supporting the graduation, which fixes the scanning distance (a), by the deformation of at least one area of the support and/or of the scanning device. The method further includes installing the support on a first object to be measured, installing the scanning device on a second object to be measured, and releasing the interlocking connection.
The particular advantage of this method rests in that the position correlation is determined only at the time of pre-mounting and that this position correlation can nevertheless be fixed in a highly exact and stable manner.
Further objects, advantages and details of the invention will become apparent from the ensuing description of an exemplary embodiment in conjunction with the accompanying drawings.